Ultra-long slump-retaining polycarboxylic acid water reducer mother liquor and preparation method thereof

Abstract

The invention relates to the field of water reducing agents, and provides a preparation method of a super-long slump-retaining polycarboxylic acid water reducing agent mother liquor in order to solve the problems that when a composite material is directly compounded with a water reducing agent, the dispersity of the composite material is poor, agglomeration is prone to occurring, the hydration degree difference of all parts of cement is large, and cracks occur. Comprising the following steps: mixing ethylene glycol monoethylene polyoxyethylene ether, acrylic acid, an ester monomer, a composite material for preparing a powdery polycarboxylate superplasticizer, sodium thiosulfate and deionized water, heating to 50-80 DEG C, adding an oxidizing agent and a reducing agent, gradually adding a chain transfer agent, and reacting to obtain a polycarboxylate superplasticizer mother solution; the ester monomers comprise one or more of hydroxyethyl acrylate, diethyl maleate and acrylic acid-2-ethylhexyl ester. The composite material and sodium thiosulfate are added in the polymerization process of the main chain and the side chain of the water reducer, so that the composite material is more easily and uniformly dispersed in the chain structure.

Description

Technical Field

[0001] The present invention relates to the field of water reducers, and in particular to an ultra-long-slump-retention polycarboxylate water reducer mother liquor and a preparation method thereof. Background Art

[0002] A water reducer is an admixture used in concrete that significantly reduces the amount of water used in the mix, thereby improving the workability and durability of the concrete. Using a water reducer allows the use of less water while maintaining the same fluidity, or increases the fluidity of the concrete without increasing the water-cement ratio. This helps improve the physical properties and durability of the concrete, while also conserving cement or increasing its strength.

[0003] The application number is 202411146655.X, and the patent name is a composite material for preparing powdered polycarboxylic acid water-reducing agent, powdered polycarboxylic acid water-reducing agent and preparation method. It discloses a composite material that can promote the solidification of water-reducing agent and improve the powdering property of water-reducing agent. The water-reducing agent prepared after being used as a raw material for water-reducing agent can also provide internal curing effect, which can effectively promote the full hydration of cement, inhibit the self-shrinkage of concrete, and thus reduce the cracking of concrete. When the humidity of the surrounding cement environment decreases, the water adsorbed by the highly absorbent composite material will be spontaneously released under the action of osmotic pressure, delaying the decrease in internal humidity, promoting further hydration of cement, and making up for the defects of traditional curing that is not in place and low curing efficiency. However, during use, the applicant found that when the composite material is directly compounded with the water-reducing agent, the dispersion of the composite material is poor and it is easy to agglomerate, which may lead to large differences in the degree of hydration of various parts of the cement and the occurrence of cracks, especially when the amount of composite material added is high. Summary of the Invention

[0004] The present invention aims to provide a polycarboxylate water-reducing agent mother liquor with ultra-long slump retention and a preparation method thereof, so as to solve the problem that when the composite material is directly compounded with the water-reducing agent, the composite material has poor dispersibility and is prone to agglomeration, which may lead to large differences in the degree of hydration of different parts of the cement and the formation of cracks.

[0005] The embodiments of the present invention are achieved through the following technical solutions:

[0006] A method for preparing a mother liquor of a polycarboxylate water-reducing agent with an ultra-long collapse retention, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether, acrylic acid, an ester monomer, a composite material for preparing a powdered polycarboxylate water-reducing agent, sodium thiosulfate, and deionized water; heating the mixture to 50° C.-80° C.; then adding an oxidizing agent and a reducing agent; and then gradually adding a chain transfer agent; and reacting to obtain a mother liquor of the polycarboxylate water-reducing agent.

[0007] The ester monomer includes one or more of hydroxyethyl acrylate, diethyl maleate and 2-ethylhexyl acrylate.

[0008] Preferably, the oxidizing agent includes hydrogen peroxide, and the reducing agent includes E51.

[0009] Preferably, the chain transfer agent includes one or more of sodium hypophosphite, mercaptoethanol and n-dodecyl mercaptan.

[0010] Preferably, the molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:4-6, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2-3:7, and the mass ratio of the ester monomer to ethylene glycol monoethylene polyoxyethylene ether is 4-10:100.

[0011] Preferably, the mass ratio of the oxidant to the reducing agent is 3-7:1, the amount of the oxidant is 0.5wt%-1.5wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the oxidant is 20%-40%.

[0012] Preferably, the mass ratio of the composite material for preparing the powdered polycarboxylate water-reducing agent to ethylene glycol monoethylene polyoxyethylene ether is 3-6:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 5-8:100.

[0013] Preferably, including:

[0014] Mix ethylene glycol monoethylene polyoxyethylene ether and deionized water, and heat to 50°C-80°C to obtain a mixed solution A;

[0015] After mixing the ester monomer and the oxidant, a mixed solution B is obtained;

[0016] After mixing acrylic acid, a reducing agent and a chain transfer agent, a mixed solution C is obtained;

[0017] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0018] Add part of mixed liquid D to mixed liquid A, gradually add mixed liquid C and add mixed liquid B in batches, cool to 35°C-45°C after reaction, add the remaining mixed liquid D, mix well and cool to room temperature to obtain polycarboxylate water-reducing agent mother liquor.

[0019] Preferably, the reaction time is 3h-5h; at 1 / 4-1 / 3 of the total reaction time, 1 / 3-1 / 2 of the total mixed solution B is added; at 1 / 2-2 / 3 of the total reaction time, 1 / 4-1 / 3 of the total mixed solution B is added; at 4 / 5-5 / 6 of the total reaction time, the remaining mixed solution B is added; and part of the mixed solution D accounts for 60%-80% of the total mixed solution D;

[0020] After adding mixed solution B, keep warm for 10-15 minutes.

[0021] Preferably, after adding the mixed solution D, the pH value of the system is adjusted to 5-6 and kept warm for 1-3 hours, and then cooled to room temperature to obtain a polycarboxylate water-reducing agent mother solution.

[0022] A mother liquor of a polycarboxylate water-reducing agent with ultra-long collapse retention prepared by the preparation method.

[0023] The present invention has at least the following beneficial effects:

[0024] The present invention adds a composite material and sodium thiosulfate during the polymerization of the main chain and side chain of a water reducer, thereby making it easier for the composite material to be evenly dispersed in the chain structure. The present invention adopts C6 polyether, which improves the swing freedom of the polyether side chain, thereby not only improving the adaptability of the mother liquor but also reducing the hindrance of the composite material during the chain growth process. The batch addition of the mixed liquid D can also reduce the influence of water absorption and steric hindrance of the composite material on the molecular weight distribution during the polymerization of the water reducer. By introducing an ester monomer and regulating the timing and amount of its addition, the release time of the water reducer can be effectively extended and the release amount per unit time can be controlled. The addition process of the chain transfer agent allows the water reducer to contain polymers of different molecular weights, while ensuring its collapse retention and durability effects and improving its dispersibility. DETAILED DESCRIPTION

[0025] In order to make the purpose, method scheme and advantages of the embodiments of the present invention clearer, the method scheme in the embodiments of the present invention is clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0026] Example 1: A method for preparing a mother solution of a super-long slump-retention polycarboxylate water-reducing agent, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 50° C. to obtain a mixed solution A;

[0027] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0028] Acrylic acid, E51 and mercaptoethanol were mixed to obtain a mixed solution C; the mass ratio of mercaptoethanol to ethylene glycol monoethylene polyoxyethylene ether was 0.2:100;

[0029] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0030] Add part of mixed solution D to mixed solution A, gradually add mixed solution C and then add mixed solution B in batches. After the reaction, cool to 35°C, add the remaining mixed solution D, mix well, and cool to room temperature to obtain the polycarboxylate superplasticizer mother solution. The reaction time is 3 hours. At 1 / 4 of the total reaction time, add 1 / 3 of the total mixed solution B; at 1 / 2 of the total reaction time, add 1 / 4 of the total mixed solution B; at 4 / 5 of the total reaction time, add the remaining mixed solution B. Part of mixed solution D accounts for 60% of the total mixed solution D.

[0031] After the addition of mixed solution B, the mixture was kept warm for 10 minutes. After the remaining amount of mixed solution D was added, the pH value of the system was adjusted to 5 and kept warm for 1 hour. Then, the mixture was cooled to room temperature to obtain the polycarboxylate superplasticizer mother solution.

[0032] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:4, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 4:100;

[0033] The mass ratio of the hydrogen peroxide to E51 is 3-7:1, the amount of the hydrogen peroxide is 0.5wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 20%;

[0034] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 3:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 5:100.

[0035] Example 2: A method for preparing a mother solution of a polycarboxylate water-reducing agent with ultra-long slump retention, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 80° C. to obtain a mixed solution A;

[0036] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0037] Acrylic acid, E51 and mercaptoethanol were mixed to obtain a mixed solution C; the mass ratio of mercaptoethanol to ethylene glycol monoethylene polyoxyethylene ether was 1:100;

[0038] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0039] Add part of mixed solution D to mixed solution A, gradually add mixed solution C and then add mixed solution B in batches. After the reaction, cool to 45°C, add the remaining mixed solution D, mix well, and cool to room temperature to obtain the polycarboxylate superplasticizer mother solution. The reaction time is 5 hours. At 1 / 3 of the total reaction time, add 1 / 2 of the total mixed solution B; at 2 / 3 of the total reaction time, add 1 / 3 of the total mixed solution B; at 5 / 6 of the total reaction time, add the remaining mixed solution B. Part of mixed solution D accounts for 80% of the total mixed solution D.

[0040] After the addition of mixed solution B, the mixture was kept warm for 15 minutes. After the remaining amount of mixed solution D was added, the pH value of the system was adjusted to 6 and kept warm for 3 hours. Then, the mixture was cooled to room temperature to obtain the polycarboxylate superplasticizer mother solution.

[0041] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:6, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 3:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 10:100;

[0042] The mass ratio of the hydrogen peroxide to E51 is 7:1, the amount of the hydrogen peroxide is 1.5wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 40%;

[0043] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 6:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 8:100.

[0044] Example 3: A method for preparing a mother solution of a super-long slump-retention polycarboxylate water-reducing agent, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 65° C. to obtain a mixed solution A;

[0045] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0046] Acrylic acid, E51 and mercaptoethanol were mixed to obtain a mixed solution C; the mass ratio of mercaptoethanol to ethylene glycol monoethylene polyoxyethylene ether was 0.6:100;

[0047] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0048] Add part of mixed solution D to mixed solution A, gradually add mixed solution C and then add mixed solution B in batches. After the reaction, cool to 40°C, add the remaining mixed solution D, mix well, and cool to room temperature to obtain the polycarboxylate superplasticizer mother solution. The reaction time is 4 hours. At 7 / 25 of the total reaction time, add 2 / 5 of the total mixed solution B; at 3 / 5 of the total reaction time, add 3 / 5 of the total mixed solution B; at 5 / 6 of the total reaction time, add the remaining mixed solution B. Part of mixed solution D accounts for 70% of the total mixed solution D.

[0049] After the addition of mixed solution B, the mixture was kept warm for 12 minutes. After the remaining amount of mixed solution D was added, the pH value of the system was adjusted to 5.5 and kept warm for 2 hours. Then, the mixture was cooled to room temperature to obtain the polycarboxylate superplasticizer mother solution.

[0050] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:5, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2.5:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 7:100;

[0051] The mass ratio of the hydrogen peroxide to E51 is 5:1, the amount of the hydrogen peroxide is 1wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 30%;

[0052] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 5:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 6:100.

[0053] Example 4: A method for preparing a mother solution of a polycarboxylate water-reducing agent with ultra-long slump retention, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 65° C. to obtain a mixed solution A;

[0054] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0055] Acrylic acid, E51, mercaptoethanol and sodium hypophosphite were mixed to obtain a mixed solution C; the mass ratio of the chain transfer agent to ethylene glycol monoethylene polyoxyethylene ether was 0.6:100; the mass ratio of mercaptoethanol to sodium hypophosphite in the chain transfer agent was 1:2;

[0056] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0057] Add part of mixed solution D to mixed solution A, gradually add mixed solution C and then add mixed solution B in batches. After the reaction, cool to 40°C, add the remaining mixed solution D, mix well, and cool to room temperature to obtain the polycarboxylate superplasticizer mother solution. The reaction time is 4 hours. At 7 / 25 of the total reaction time, add 2 / 5 of the total mixed solution B; at 3 / 5 of the total reaction time, add 3 / 5 of the total mixed solution B; at 5 / 6 of the total reaction time, add the remaining mixed solution B. Part of mixed solution D accounts for 70% of the total mixed solution D.

[0058] After the addition of mixed solution B, the mixture was kept warm for 12 minutes. After the remaining amount of mixed solution D was added, the pH value of the system was adjusted to 5.5 and kept warm for 2 hours. Then, the mixture was cooled to room temperature to obtain the polycarboxylate superplasticizer mother solution.

[0059] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:5, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2.5:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 7:100;

[0060] The mass ratio of the hydrogen peroxide to E51 is 5:1, the amount of the hydrogen peroxide is 1wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 30%;

[0061] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 5:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 6:100.

[0062] Comparative Example 1: A method for preparing a mother liquor of a super-long slump-retention polycarboxylate water-reducing agent, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 65° C. to obtain a mixed solution A;

[0063] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0064] Acrylic acid, E51, mercaptoethanol and sodium hypophosphite were mixed to obtain a mixed solution C; the mass ratio of the chain transfer agent to ethylene glycol monoethylene polyoxyethylene ether was 0.6:100; the mass ratio of mercaptoethanol to sodium hypophosphite in the chain transfer agent was 1:2;

[0065] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0066] Gradually add Mixture C to Mixture A and then add Mixture B in batches. After the reaction, cool to 40°C, add Mixture D, mix thoroughly, and cool to room temperature to obtain the polycarboxylate superplasticizer mother liquor. The reaction time is 4 hours. At 7 / 25 of the total reaction time, add 2 / 5 of the total Mixture B. At 3 / 5 of the total reaction time, add 3 / 5 of the total Mixture B. At 5 / 6 of the total reaction time, add the remaining Mixture B. Some Mixture D accounts for 70% of the total Mixture D.

[0067] After the addition of mixed solution B, the mixture was kept warm for 12 minutes. After the remaining amount of mixed solution D was added, the pH value of the system was adjusted to 5.5 and kept warm for 2 hours. Then, the mixture was cooled to room temperature to obtain the polycarboxylate superplasticizer mother solution.

[0068] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:5, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2.5:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 7:100;

[0069] The mass ratio of the hydrogen peroxide to E51 is 5:1, the amount of the hydrogen peroxide is 1wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 30%;

[0070] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 5:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 6:100.

[0071] Comparative Example 2: A method for preparing a mother liquor of a super-long slump-retention polycarboxylate water-reducing agent, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 65° C. to obtain a mixed solution A;

[0072] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0073] Acrylic acid, E51, mercaptoethanol and sodium hypophosphite were mixed to obtain a mixed solution C; the mass ratio of the chain transfer agent to ethylene glycol monoethylene polyoxyethylene ether was 0.6:100; the mass ratio of mercaptoethanol to sodium hypophosphite in the chain transfer agent was 1:2;

[0074] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0075] Add part of mixed solution D and all of mixed solution B to mixed solution A, gradually add mixed solution C, cool to 40°C after reaction, add the remaining mixed solution D, mix well and cool to room temperature to obtain polycarboxylate superplasticizer mother solution. The reaction time is 4 hours;

[0076] After the addition of mixed solution B, the mixture was kept warm for 12 minutes. After the remaining amount of mixed solution D was added, the pH value of the system was adjusted to 5.5 and kept warm for 2 hours. Then, the mixture was cooled to room temperature to obtain the polycarboxylate superplasticizer mother solution.

[0077] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:5, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2.5:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 7:100;

[0078] The mass ratio of the hydrogen peroxide to E51 is 5:1, the amount of the hydrogen peroxide is 1wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 30%;

[0079] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 5:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 6:100.

[0080] Comparative Example 3: A method for preparing a mother liquor of a super-long slump-retention polycarboxylate water-reducing agent, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 65° C. to obtain a mixed solution A;

[0081] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0082] Acrylic acid, E51, mercaptoethanol and sodium hypophosphite were mixed to obtain a mixed solution C; the mass ratio of the chain transfer agent to ethylene glycol monoethylene polyoxyethylene ether was 0.6:100; the mass ratio of mercaptoethanol to sodium hypophosphite in the chain transfer agent was 1:2;

[0083] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0084] Add part of mixed solution D to mixed solution A, gradually add mixed solution C and then add mixed solution B in batches. After the reaction, cool to 40°C, add the remaining mixed solution D, mix well, and cool to room temperature to obtain the polycarboxylate superplasticizer mother solution. The reaction time is 4 hours. At 7 / 25 of the total reaction time, add 2 / 5 of the total mixed solution B; at 3 / 5 of the total reaction time, add 3 / 5 of the total mixed solution B; at 5 / 6 of the total reaction time, add the remaining mixed solution B. Part of mixed solution D accounts for 70% of the total mixed solution D.

[0085] After the mixture B is added, keep warm for 12 minutes, add the remaining amount of the mixture D, and then cool to room temperature to obtain the polycarboxylate water-reducing agent mother solution.

[0086] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:5, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2.5:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 7:100;

[0087] The mass ratio of the hydrogen peroxide to E51 is 5:1, the amount of the hydrogen peroxide is 1wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 30%;

[0088] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 5:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 6:100.

[0089] Comparative Example 4: A method for preparing a mother liquor of a polycarboxylate water-reducing agent with ultra-long slump retention, comprising: mixing ethylene glycol monoethylene polyoxyethylene ether with deionized water, and heating the mixture to 65° C. to obtain a mixed solution A;

[0090] Diethyl maleate and hydrogen peroxide are mixed to obtain a mixed solution B;

[0091] Acrylic acid, E51, mercaptoethanol and sodium hypophosphite were mixed to obtain a mixed solution C; the mass ratio of the chain transfer agent to ethylene glycol monoethylene polyoxyethylene ether was 0.6:100; the mass ratio of mercaptoethanol to sodium hypophosphite in the chain transfer agent was 1:2;

[0092] The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D;

[0093] Add part of mixed solution D to mixed solution A, gradually add mixed solution C and then add mixed solution B in batches. After the reaction, cool to 40°C, add the remaining mixed solution D, mix well, and cool to room temperature to obtain the polycarboxylate superplasticizer mother solution. The reaction time is 4 hours. At 7 / 25 of the total reaction time, add 2 / 5 of the total mixed solution B; at 3 / 5 of the total reaction time, add 3 / 5 of the total mixed solution B; at 5 / 6 of the total reaction time, add the remaining mixed solution B. Part of mixed solution D accounts for 70% of the total mixed solution D.

[0094] After the addition of mixed solution B, the mixture was kept warm for 12 minutes. After the remaining amount of mixed solution D was added, the pH value of the system was adjusted to 5.5, and then cooled to room temperature to obtain the polycarboxylate superplasticizer mother solution.

[0095] The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:5, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2.5:7, and the mass ratio of diethyl maleate to ethylene glycol monoethylene polyoxyethylene ether is 7:100;

[0096] The mass ratio of the hydrogen peroxide to E51 is 5:1, the amount of the hydrogen peroxide is 1wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the hydrogen peroxide is 30%;

[0097] The mass ratio of the composite material for preparing the powdered polycarboxylate water reducer to ethylene glycol monoethylene polyoxyethylene ether is 5:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 6:100.

[0098] experiment:

[0099] The composite material of powder polycarboxylate water reducer is prepared in Example 2 of the patent with application number 202411146655.X and patent name: A composite material for preparing powder polycarboxylate water reducer, powder polycarboxylate water reducer and preparation method.

[0100] Test 1:

[0101] Concrete performance test: The water-reducing agent mother liquors prepared according to the preparation methods of Examples 1-4 and Comparative Examples 1-4 were spray-dried to obtain powdered water-reducing agent samples. The samples were then subjected to performance tests in accordance with GB8076-2008 "Concrete Admixtures". The test results are shown in Table 1.

[0102] Table 1

[0103]

[0104] From the test results of Examples 1-4, it can be seen that the water-reducing agent mother liquor prepared by the preparation method provided by the present invention has good performance and the chain transfer agent prepared by compounding mercaptoethanol and sodium hypophosphite has better effect.

[0105] From the comparison between Comparative Examples 1-4 and Example 4, it can be seen that the addition of mixed solution B and mixed solution D, the adjustment of pH value, and the heat preservation operation after pH adjustment all affect the product performance.

[0106] Test 2:

[0107] Micro-infrared thermal imaging was used to detect cracks in concrete. No cracks were observed when the water-reducing agent mother solutions prepared according to the preparation methods provided in Examples 1-4 and Comparative Examples 3-4 were added to the concrete. However, cracks were observed when the water-reducing agent mother solutions prepared according to the preparation methods provided in Comparative Examples 1-2 were added to the concrete. The cracking was particularly severe in Comparative Example 2.

[0108] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a super-long collapse-retention polycarboxylate water-reducing agent mother liquor, characterized in that: include: Ethylene glycol monoethylene polyoxyethylene ether, acrylic acid, ester monomer, a composite material for preparing a powdered polycarboxylate water-reducing agent, sodium thiosulfate and deionized water are mixed, heated to 50°C-80°C, and then an oxidizing agent and a reducing agent are added, and then a chain transfer agent is gradually added to obtain a polycarboxylate water-reducing agent mother liquor after reaction; The ester monomer includes one or more of hydroxyethyl acrylate, diethyl maleate and 2-ethylhexyl acrylate.

2. The preparation method according to claim 1, characterized in that The oxidizing agent includes hydrogen peroxide, and the reducing agent includes E51.

3. The preparation method according to claim 2, characterized in that The chain transfer agent comprises: one or more of sodium hypophosphite, mercaptoethanol and n-dodecyl mercaptan; the mass ratio of the chain transfer agent to ethylene glycol monoethylene polyoxyethylene ether is 0.2-1:

100.

4. The preparation method according to claim 1, characterized in that The molar ratio of ethylene glycol monoethylene polyoxyethylene ether to acrylic acid is 1:4-6, the mass ratio of ethylene glycol monoethylene polyoxyethylene ether to deionized water is 2-3:7, and the mass ratio of the ester monomer to ethylene glycol monoethylene polyoxyethylene ether is 4-10:

100.

5. The preparation method according to claim 1, characterized in that The mass ratio of the oxidant to the reducing agent is 3-7:1, the amount of the oxidant is 0.5wt%-1.5wt% of ethylene glycol monoethylene polyoxyethylene ether, and the mass concentration of the oxidant is 20%-40%.

6. The preparation method according to claim 1, characterized in that The mass ratio of the composite material for preparing the powdered polycarboxylate water-reducing agent to ethylene glycol monoethylene polyoxyethylene ether is 3-6:100, and the mass ratio of sodium thiosulfate to ethylene glycol monoethylene polyoxyethylene ether is 5-8:

100.

7. The preparation method according to any one of claims 1 to 6, characterized in that include: Mix ethylene glycol monoethylene polyoxyethylene ether and deionized water, and heat to 50°C-80°C to obtain a mixed solution A; After mixing the ester monomer and the oxidant, a mixed solution B is obtained; After mixing acrylic acid, a reducing agent and a chain transfer agent, a mixed solution C is obtained; The composite material for preparing the powdered polycarboxylate water-reducing agent and sodium thiosulfate are mixed to obtain a mixed solution D; Add part of mixed liquid D to mixed liquid A, gradually add mixed liquid C and add mixed liquid B in batches, cool to 35°C-45°C after reaction, add the remaining mixed liquid D, mix well and cool to room temperature to obtain polycarboxylate water-reducing agent mother liquor.

8. The preparation method according to claim 7, characterized in that The reaction time is 3h-5h; at 1 / 4-1 / 3 of the total reaction time, add 1 / 3-1 / 2 of the total mixed solution B; at 1 / 2-2 / 3 of the total reaction time, add 1 / 4-1 / 3 of the total mixed solution B; at 4 / 5-5 / 6 of the total reaction time, add the remaining mixed solution B; part of the mixed solution D accounts for 60%-80% of the total mixed solution D; After adding mixed solution B, keep warm for 10-15 minutes.

9. The preparation method according to claim 8, characterized in that After adding the remaining mixed solution D, the pH value of the system is adjusted to 5-6 and kept warm for 1-3 hours, and then cooled to room temperature to obtain the polycarboxylate water-reducing agent mother solution.

10. A mother liquor of a polycarboxylate water-reducing agent with ultra-long slump retention obtained by the preparation method according to any one of claims 1 to 9.

Images